1. Field of the Invention
The present invention relates in general to pipelines and, in particular, to an apparatus and method to contain pipeline leaks.
2. Brief Description of Related Art
Following the Gulf of Mexico oil spill in 2010, a number of initiatives have been proposed and acted upon in order to provide a rapid response to contain oil spills, but these initiatives are focused on systems to shut down a leaking well. For example, a consortium is supporting development of a system that may eventually be able to contain wells in water up to 10,000 feel deep, with pressures of up to 15,000 pounds per square inch and collecting up to 100,000 barrels of oil and gas a day. An interim system is currently available that can accommodate 15,000-pound-per-square-inch wells in up to 8,000 feet of water and collecting up to 60,000 barrels a day. These initiatives, however, do not address the issue of pipeline leaks.
Wear and tear on oil and gas pipelines cannot be avoided, as corrosion and accidental damage can occur when least expected. In response to this, the South East Asia Pipeline Operators Group (SEAPOG) identified the Emergency Pipeline Repair Equipment Sharing (EPRES) initiative in April 2007. The EPRES provides a mechanism that mitigates risk and addresses the timely repair of pipelines. Shared services and spare equipment exchanges are common practice among pipeline operators. The basis of a mutual agreement where willing parties share their inventories is the key to addressing timely mitigation of pipeline emergencies and may provide an alternative route to developing a prototype of the proposed apparatus.
In terms of subsea pipeline leaks, emphasis is given to incorporation during design and construction phases of the necessary requirements to facilitate execution of future repairs, including material selection, welding, isolation, decontamination, repairs engineering (free spans, pipeline lifting), repairs contingency materials and procedures. As such, emergency pipeline repair equipment is generally accessible.
There are generally two different repair solutions depending on the size of the damage. When damage is minor, such as a dent that is small enough that a pipeline pig can still pass through the pipeline (a “piggable” dent), and pin-hole leaks, the damaged section does not need to be cut out. The repair includes cleaning the pipe surface in the vicinity of the leak and then installing a leak repair/reinforcement clamp around the damaged part. The factors for determining whether or not to cut out the damaged section of pipe include future operational piggability, operator pipeline integrity management (“PIM”) policy, and operator pipeline repair philosophy.
For major damage, such as non-piggable dents or rupture, the damaged section must be cut out and replaced by a new section of pipe. This type of repair can include hot tapping, isolation, decommissioning and re-commissioning. Furthermore, a repair of this nature involves both subsea and on the surface activities, including a marine spread consisting of a Diving Support Vessel (“DSV”), diving spread, survey vessels and transportation barges, specialized pipeline preparations and repair equipment and pipeline connection equipment.
It is not always possible to immediately stop fluid flow and depressurize a pipeline to make a permanent repair. Therefore there is a need for a way to stop pipeline fluid from leaking into the surrounding environment until the pipeline can be shut down, depressurized, and permanently repaired.